A Comparison of Cooperative Transmission Schemes for the ultiple Access elay Channel André Angierski andre.angierski@uni-rostock.de 0/03/7 UNIVESITY OF OSTOCK FACULTY OF COPUTE SCIENCE AND ELECTICAL ENGINEEING ANDÉ ANGIESKI
Outline otivation System odel eference Scheme Cooperative Schemes esults Conclusion 0/03/7 UNIVESITY OF OSTOCK FACULTY OF COPUTE SCIENCE AND ELECTICAL ENGINEEING ANDÉ ANGIESKI
otivation Transmitting independent copies of the signal generates diversity and can effectively combat the deleterious effects of fading [Nosratinia, Hunter, Hedayat: Cooperative Communication in Wireless Networks ] Spatial diversity Several independent transmissions of same information User cooperation diversity Joint processing at relay and destination for different users Focus on transmission schemes and detection algorithms No focus on optimization of throughput or code rate 0/03/7 UNIVESITY OF OSTOCK FACULTY OF COPUTE SCIENCE AND ELECTICAL ENGINEEING ANDÉ ANGIESKI 3
The ultiple Access elay Channel (AC S i ultiple users, one relay and one destination D PS Constraints Two users Half-duple transmission without interference in TDA mode with three time slots Two fied positions for the relay close to close to S S i S D PSfrag D D S S 0/03/7 UNIVESITY OF OSTOCK FACULTY OF COPUTE SCIENCE AND ELECTICAL ENGINEEING ANDÉ ANGIESKI 4
Physical Layer Parameters ayleigh block fading (fading coefficient n = 4 y = a d = + n Gaussian noise Path-loss eponent Perfect channel state information for receiving devices a Bit-Interleaved Coded odulation (BIC and -QA ecursive systematic convolutional code with generator polynomials and code rate C = = Error free decoding at (5; 3 8 0/03/7 UNIVESITY OF OSTOCK FACULTY OF COPUTE SCIENCE AND ELECTICAL ENGINEEING ANDÉ ANGIESKI 5
Transmission Schemes First and second time slot: transmission with BIC forwards information from two users within third time slot S i! ; D! D eference scheme: Separate coding and transmission atching slot size by appropriate puncturing Cooperative schemes XO processing of information bits Superposition apping odulation Boost Joint coding and puncturing 0/03/7 UNIVESITY OF OSTOCK FACULTY OF COPUTE SCIENCE AND ELECTICAL ENGINEEING ANDÉ ANGIESKI 6
eference Scheme Institute of PSfrag repla C = Separate encoding and puncturing to at Sequential transmission Two independent parallel concatenated codes for and S S u S S c S S C S u C P C c u C P C c L ( c ^ S L a ( u ^ S C L ( u ^ S L a ( u ^ u S S c S S C S L ( u ^ C L ( c ^ 0/03/7 UNIVESITY OF OSTOCK FACULTY OF COPUTE SCIENCE AND ELECTICAL ENGINEEING ANDÉ ANGIESKI 7
Cooperative Scheme: XO Interpretation as lossy compression etrieving information requires direct links of appropriate quality PSfrag replacem u S c S S C S S L ( c ^ S L a ( u ^ S C L ( u ^ S u u c C u L ( c ^ L a ( u ^ C L ( u ^ L a ( u ^ S u S c S S C S S L ( u ^ S C L ( c ^ S 0/03/7 UNIVESITY OF OSTOCK FACULTY OF COPUTE SCIENCE AND ELECTICAL ENGINEEING ANDÉ ANGIESKI 8
Cooperative Schemes: Superposition apping Disjoint data processing at for both BIC streams Joint transmission by superposition of symbols Joint demapping for and y = + e j¼=4 p L ( c ^ L ( c ^ PSfrag u S S c S C S S L ( c ^ S L a ( u ^ S C L ( u ^ S u C c u C c L a ( u ^ u S c S S C S S L ( u ^ C L ( c ^ PSfrag 0/03/7 UNIVESITY OF OSTOCK FACULTY OF COPUTE SCIENCE AND ELECTICAL ENGINEEING ANDÉ ANGIESKI 9
Cooperative Schemes: odulation Boost Joint encoding at with doubled number of code bits compared to Increased number of bits per symbol at 4-QA ( 6-QA (, 6-QA ( 56-QA ( S i S i S i PSfrag r u S c S S C S S L ( c ^ S L a ( u ^ S C L ( u ^ S u u c C u L ( u ^ C L ( c ^ L a ( u ^ u S c S S C S S L ( c ^ S L a ( u ^ S C L ( u ^ S 0/03/7 UNIVESITY OF OSTOCK FACULTY OF COPUTE SCIENCE AND ELECTICAL ENGINEEING ANDÉ ANGIESKI 0
Cooperative Schemes: Joint Coding & Puncturing Joint encoding at ( Puncturing to code rate at with same number of code bits as for C = PSfrag replace S i u S S c S C S S L ( c ^ S L a ( u ^ S C L ( u ^ S u u c C P u C L ( u ^ C L ( c ^ L a ( u ^ u S S c S C S S L ( c ^ S L a ( u ^ S C L ( u ^ S 0/03/7 UNIVESITY OF OSTOCK FACULTY OF COPUTE SCIENCE AND ELECTICAL ENGINEEING ANDÉ ANGIESKI
BE Institute of esults: 4-QA 0 0 0-0 - 0-3 eference XO Superpos.apping 0-4 odulation Boost Joint Coding&Punc. close to S close to D 0-5 - 0-5 0 5 0 5 0 E b /N 0 [db] 0/03/7 UNIVESITY OF OSTOCK FACULTY OF COPUTE SCIENCE AND ELECTICAL ENGINEEING ANDÉ ANGIESKI
BE Institute of esults: 6-QA 0 0 0-0 - 0-3 eference XO Superpos.apping 0-4 odulation Boost Joint Coding&Punc. close to S close to D 0-5 - 0-5 0 5 0 5 0 E b /N 0 [db] 0/03/7 UNIVESITY OF OSTOCK FACULTY OF COPUTE SCIENCE AND ELECTICAL ENGINEEING ANDÉ ANGIESKI 3
Conclusions No diversity gain Gain due to cooperation Performance for XO dependent on quality of both direct paths Drawback for Superposition apping especially for modulation schemes of higher order Best results for odulation Boost and Joint Coding & Puncturing 0/03/7 UNIVESITY OF OSTOCK FACULTY OF COPUTE SCIENCE AND ELECTICAL ENGINEEING ANDÉ ANGIESKI 4
THANK YOU FO YOU ATTENTION! 0/03/7 UNIVESITY OF OSTOCK FACULTY OF COPUTE SCIENCE AND ELECTICAL ENGINEEING ANDÉ ANGIESKI 5